DSpace Collection:http://hdl.handle.net/10204/9422015-03-31T22:04:32Z2015-03-31T22:04:32ZImproving settlement type classification of aerial imagesMdakane, Lvan den Bergh, FMoodley, Dhttp://hdl.handle.net/10204/79422015-03-12T21:55:33Z2014-10-01T00:00:00ZTitle: Improving settlement type classification of aerial images
Authors: Mdakane, L; van den Bergh, F; Moodley, D
Abstract: The rapid increase in population and migration to urban areas has caused a pronounced increase in human settlements around the world. The diversity of land features, mixed-use settlements, terrain, and heterogeneity of building materials and neighbourhood structure limit the use of a fixed set of indicators to identify these areas. In many parts of the developing world, census and socio-economic data are severely lacking, outdated, or not collected at neighbourhood scales. Using remote sensing data, an automated method can be used to help identify human settlements in a fixed, repeatable and timely manner. The main contribution of this work is to improve generalisation on settlement type classification of aerial imagery. Images acquired at different dates (multitemporal imagery) tend to exhibit pronounced viewing- and illumination geometry effects, which result in a poor generalization performance in settlement type classification tasks. The study investigated the influence of contrast in settlement type classification tasks by measuring classification accuracies using Local Binary Patterns without contrast measures and with local contrast measures (denoted as the extended LBP or LBP/VAR). This was achieved by recognizing fundamental properties of local image texture, i.e., a combination of structural and statistical approaches: the local binary pattern detects micro structures (e.g., edges, lines, spots, flat areas) while variance measures detect the underlying local contrast distribution. The extended LBP method was evaluated using a support vector machine classifier for cross-date (training and test images acquired at different dates) and same-date analysis. The extended LBP results showed strong spatial and temporal generalisation ability thus we can conclude that adding local contrast measures can significantly improve the classification of human settlements from aerial images.
Description: Tenth International Conference of the African Association of Remote Sensing of the Environment, University of Johannesburg, South Africa, 27-31 October 2014. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website.2014-10-01T00:00:00ZInvestigating the environmental costs of deteriorating road conditions in South AfricaMashoko, LBean, WLSteyn, WJvdMhttp://hdl.handle.net/10204/78732015-02-09T21:55:15Z2014-07-01T00:00:00ZTitle: Investigating the environmental costs of deteriorating road conditions in South Africa
Authors: Mashoko, L; Bean, WL; Steyn, WJvdM
Abstract: The potential environmental impacts of deteriorating road conditions on logistics systems and the national economy have not received significant attention. This study gives an estimate of the potential environmental costs of deteriorating road network conditions in South Africa. This paper is an extension of past studies dealing with the potential effects of deteriorating road conditions in South Africa and focuses on comparing the environmental impacts of freight transportation on the national and provincial road networks. The International Panel on Climate Change (IPCC) guidelines for estimating carbon dioxide emissions from vehicles was used to determine the potential environmental costs. Preliminary calculations show increased environmental costs on the provincial road network when used for freight transportation as compared to the national road network. This is because the national road network is in a much better condition compared to the provincial road network. Finally, recommendations for future enhancements of the methodology to quantify the environmental impacts of deteriorating road conditions are given.
Description: The 33rd Annual Southern African Transport Conference and Exhibition (SATC), CSIR International Convention Centre, Pretoria, 7-10 July 20142014-07-01T00:00:00ZDry season biomass estimation as an indicator of rangeland quantity using multi-scale remote sensing dataRamoelo, ACho, MAhttp://hdl.handle.net/10204/78522015-02-09T21:55:21Z2014-10-01T00:00:00ZTitle: Dry season biomass estimation as an indicator of rangeland quantity using multi-scale remote sensing data
Authors: Ramoelo, A; Cho, MA
Abstract: For grazing, biomass is the main indicator of rangeland quantity, which is crucial to determine the amount of food available for animals (grazers), including livestock. Livestock production in the rural communities of the world, including Africa, is the main source of income and hence livelihood. Biomass information during dry season is not only important for grazing but also for determining the fuel load for fire risk. During dry season, grazers are mainly limited by grass quantity than quality. Therefore, it is important to quantify the variability of biomass during dry season to inform decision makers on planning and management of the grazing systems. Remote sensing provides opportunity to successfully estimate biomass in natural and agricultural areas. The conventional approach makes use of the vegetation indices such as the normalized difference vegetation index (NDVI), which is a measure of vegetation greenness. The use of vegetation indices has been successful during wet periods where vegetation is green and photosynthetic active. During dry season, biomass estimation is always not plausible using vegetation indices. The aim of this study is to estimate dry biomass using the multi-scale remote sensing data in the savanna ecosystem. Field data was collected in August 2013, and concerted to the acquisition of the satellite image from RapidEye and Landsat 8. Random forest algorithm (RF) was used to predict biomass using the band reflectance data, from RapidEye and Landsat 8 respectively. The results show that RF combined with RapidEye explained over 85% of biomass variation, as compared to 81% explained by RF with Landsat 8 data. For regional assessment of biomass as an indicator of rangeland quantity, high spatial resolution data can be used for calibration and validation. This study demonstrates that dry season biomass can be estimated using remote sensing, and it is important for understanding grazing and feeding patterns of animals, including livestock and wildlife.
Description: 10th International Conference on African Association of Remote Sensing of Environment (AARSE) 2014, University of Johannesburg, 27-31 October 20142014-10-01T00:00:00ZNeutralization and attenuation of metal species in acid mine drainage and mine leachates using magnesite: a batch experimental approachMasindi, VGitari, WMTutu, HDe Beer, MNekhwevha, Nhttp://hdl.handle.net/10204/78382015-01-14T21:55:19Z2014-08-01T00:00:00ZTitle: Neutralization and attenuation of metal species in acid mine drainage and mine leachates using magnesite: a batch experimental approach
Authors: Masindi, V; Gitari, WM; Tutu, H; De Beer, M; Nekhwevha, N
Abstract: This paper evaluates the potential application of amorphous magnesite for remediation of Acid Mine Drainage (AMD). Magnesite was mixed with simulated AMD at specific S/L ratios and agitated in an orbital shaker and its capacity to remove metals and neutralize the acidity assessed over time. XRF analysis showed that magnesite contains MgO (88.54 %) as the major element. XRD revealed that magnesite is amorphous and contains periclase as major mineral phase. Results indicate that contact of AMD with magnesite leads to an increase in pH (pH=10), and a reduction in EC, TDS and metal concentration to below DWAF guidelines. PHREEQC geochemical modeling predicted precipitation of Al, Fe, Mn, Mg bearing mineral phases could be responsible for attenuation of most metal species. However a high proportion of alkali and alkaline earth metals remained in the treated water which might require post treatment polishing.
Description: Annual International Mine Water Association Conference – An Interdisciplinary Response to Mine Water Challenges, China University of Mining and Technogy, China, China, 18-22 August 2014. Abstract attached2014-08-01T00:00:00Z